Barrel side and pulsed power supply module are two crucial parts of an electromagnetic launcher (EML), which affects the efficiency. One of the most important features in the barrel side is the shape of the armature. In this study, the shape of the armature is optimized by using independent variables to define the exact geometry of the armature. The main goal is to maximize the muzzle kinetic energy of the projectile. Armature geometry is divided into pieces which are used in the optimization algorithm as independent variables. Finite element method (FEM) is used to calculate the fitness function of the genetic algorithm (GA).